Physical oceanography   总被引：2，自引：0，他引：2  

K. Yoshida  K. Takano  T. Teramoto  Y. Toba  Y. Nagata  K. Kajiura  T. Nan'nichi  N. Iwata  T. Takahashi  M. Chaen  T. Tabata 《Journal of Oceanography》1971,27(6):248-264

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GEK measurements in a shallow water region     

Yutaka Nagata  Kimie Yonemura  Hideo Nishida 《Journal of Oceanography》1981,37(1):21-29

Evidence for the applicability of GEK (Geomagnetic Electrokinetography) measurements to shallow water regions is provided from observations in the shelf region of the East China Sea. The reason for the effectiveness of GEK measurements in this case is investigated theoretically, and it is shown to be attributable to the existence of a thick conductive sedimentary layer. In addition, it is shown that low conductive basement rock can be regarded as a good conductor for GEK measurements if the current width is broad enough and if the ratio of current width to water depth is larger than the resistivity ratio of basement rock to sea water. This implies that barotropic tidal currents can be measured with GEK in any ocean on the earth if they have significant magnitudes.  相似文献   

Biogeochemical Variation in Dimethylsulfide, Phytoplankton Pigments and Heterotrophic Bacterial Production in the Subarctic North Pacific during Summer     

Kazushi Aranami  Shuichi Watanabe  Shizuo Tsunogai  Masato Hayashi  Ken Furuya  Toshi Nagata 《Journal of Oceanography》2001,57(3):315-322

Dimethylsulfide (DMS), chlorophyll a (Chl-a), accessory pigments (fucoxanthin, peridinin and 19-hexanoyloxyfucoxanthin), and bacterial production (BP) were measured in the surface layer (0–100 m) of the subarctic North Pacific, including the Bering Sea, during summer (14 July–5 September, 1997). In surface sewater, the concentrations of DMS and Chl-a varied widely from 1.3 to 13.2 nM (5.1 ± 3.0 nM, mean ± S.D., n = 48) and from 0.1 to 2.4 µg L^–1 (0.6 ± 0.6 µg L^–1, n = 24), respectively. In the subarctic North Pacific, DMS to Chl-a ratios (DMS/Chl-a) were higher on the eastern side than the western side (p < 0.0001). Below the euphotic zone, DMS/Chl-a ratios were law and the correlation between DMS and Chl-a was relatively strong (r ² = 0.700, n = 27, p < 0.0001). In the euphotic zone, DMS/Chl-a ratios were higher and the correlation between DMS and Chl-a was weak (r ² = 0.128, n = 50, p = 0.01). The wide variation in DMS/Chl-a ratios would be at least partially explained by the geographic variation in the taxonomic composition of phytoplankton, because of the negative correlation between DMS/Chl-a and fucoxanthin-to-Chl-a ratios (Fuc/Chl-a) (r ² = 0.476, n = 26, p = 0.0001). Furthermore, there was a positive correlation between DMS and BP (r ² = 0.380, n = 19, p = 0.005). This suggests that BP did not represent DMS and dimethylsulfoniopropionate (DMSP) removal by bacterial consumption but rather DMSP degradation to DMS by bacterial enzyme.  相似文献   

The structure of the kuroshio front in the vicinity of separation point where the Kuroshio leaves the Japanese coast     

Hong-Ryeol Shin  Yutaka Michida  Yutaka Nagata 《Journal of Oceanography》1991,47(4):111-125

By using existing data obtained in the offshore area from the Boso Peninsula to the Joban Coast, it was shown that the double structure of the Kuroshio Front — which is usually found along the northern edge of the Kuroshio Extension to the east 143°E (Nagataet al., 1986 ; Shinet al., 1988) — is hardly found at the edge of the Kuroshio when it is flowing along the Japanese coast or in the area to the west of 142°E. It was suggested that the cold and fresh water core beneath the density front of the double structure originates from the fresh and cold Oyashio Water which is captured beneath the Kuroshio Front just off the Kashima Coast. The double structure of the Kuroshio Front would be generated and developed very rapidly in the region between 142°E and 143°E just after the Kuroshio leaves the Japanese coast.  相似文献   

Infrared polarization of venus: Its periodic fluctuations and evidence for thin haze     

Tetsuya Nagata  Shuji Sato  Tadashi Mukai  Sonoyo Mukai 《Icarus》1984,57(1):125-134

Infrared polarimetry of Venus over the phase angles from 18 to 171° has been made extending previous measurements (S. Sato, K. Kawara, Y. Kobayashi, H. Okuda, K. Noguchi, T. Mukai, and S. Mukai (1980). Icarus43, 288) in both wavelength λ and phase angle θ. The results of polarization measurements at 2.25 μm ? λ ? 5.0 μm are (i) small positive and negative values at K(2.25 μm), (ii) a remarkable variation with λ in the CVF(2.2?4.2μm) filter region, (iii) a nearly smooth curve as a function of θ having a peak value of ～36% at θ ～ 90° at both 3.6 μm and L′(3.8 μm), and (iv) a decrease with increasing field of view at M(5.0 μm) due to the contamination of thermal emission from the dark crescent. Furthermore, at 3.6 μm and L′(3.8 μm), (v) higher values at the poles than at the equator and (vi) 4.5- to 5.9-day periodic fluctuations are also found. From a comparison with model calculations, the results confirm the existence of a thin haze layer consisting of submicron-size particles above the main clouds of Venus; e.g., its optical thickness is about 0.1 at λ ～ 0.94 μm. In addition, result (vi) could be explained by a variation of the optical thickness of the haze layer or that of the brightness temperature of the main clouds.  相似文献   

General expressions for internal deformation fields due to a dislocation source in a multilayered elastic half-space     

Yukitoshi Fukahata  Mitsuhiro Matsu'ura 《Geophysical Journal International》2005,161(2):507-521

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The Dynamic Fracture Process in Rocks Under High-Voltage Pulse Fragmentation     

Sang Ho Cho  Sang Sun Cheong  Mitsuhiro Yokota  Katsuhiko Kaneko 《Rock Mechanics and Rock Engineering》2016,49(10):3841-3853

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Preface     

Makio?C.?HondaEmail author  Hiroaki?Saito  Eitarou?Oka  Toshi?Nagata 《Journal of Oceanography》2016,72(3):339-339

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Depth-dependent and seasonal variability in archaeal community structure in the subarctic and subtropical western North Pacific     

Ryo Kaneko  Toshi Nagata  Shotaro Suzuki  Koji Hamasaki 《Journal of Oceanography》2016,72(3):427-438

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A kinematic model for evolution of island arc-trench systems   总被引：1，自引：0，他引：1  

Toshinori Sato  Mitsuhiro Matsu'ura 《Geophysical Journal International》1993,114(3):512-530

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